Evaluation method and manufacturing method of light-emitting element material, manufacturing method of light-emitting element, and light-emitting device and electric appliance having light-emitting element

Abstract

The present invention provides an evaluation method for evaluating whether a light-emitting element material to be evaluated is suitable for a host material or a guest material. By carrying out a first step of measuring absorption intensity of a light-emitting element material and a second step of irradiating the light-emitting element material with light for a predetermined period of time, repeatedly; thereby a change in absorption intensity with time is evaluated so that whether the light-emitting material is suitable for a host material or a guest material can be distinguished. The light emitted to the light-emitting element material preferably has a wavelength component which is absorbed by a skeleton which contributes to excitation of the light-emitting element material.

1. An evaluation method of a light-emitting element material, comprising the steps of:
 measuring a first absorption intensity of the light-emitting element material; 
 applying stress to the light-emitting element material after measuring the first absorption intensity; 
 measuring a second absorption intensity of the light-emitting element material after applying the stress; and 
 evaluating photochemical stability of the light-emitting element material based on the first absorption intensity and the second absorption intensity. 
 
   
   
     2. An evaluation method of a light-emitting element material, comprising the steps of:
 a first measuring a first absorption intensity of the light-emitting element material;
 applying stress to the light-emitting element material after the first measuring step; 
 a second measuring a second absorption intensity of the light-emitting element material after applying the stress; and 
 evaluating photochemical stability of the light-emitting element material based on the first absorption intensity and the second absorption intensity, 
 wherein the second measuring step and the applying step are repeatedly carried out. 
 
 
   
   
     3. A manufacturing method of a light-emitting device including a light-emitting layer containing a light-emitting element material between a first electrode and a second electrode, comprising the steps of:
 measuring a first absorption intensity of the light-emitting element material;
 applying stress to the light-emitting element material after measuring the first absorption intensity; 
 measuring a second absorption intensity of the light-emitting element material after applying the stress; 
 evaluating photochemical stability of the light-emitting element material based on the first absorption intensity and the second absorption intensity; and 
 forming the light-emitting layer containing the light-emitting element material after the evaluating step. 
 
 
   
   
     4. An evaluation method of a light-emitting element material according to  claim 1 , wherein the light-emitting element material is an anthracene derivative. 
   
   
     5. An evaluation method of a light-emitting element material according to  claim 2 , wherein the light-emitting element material is an anthracene derivative. 
   
   
     6. A manufacturing method of a light-emitting device according to  claim 3 , wherein the light-emitting element material is an anthracene derivative. 
   
   
     7. An evaluation method of a light-emitting element material according to  claim 1 , wherein the stress is light. 
   
   
     8. An evaluation method of a light-emitting element material according to  claim 2 , wherein the stress is light. 
   
   
     9. A manufacturing method of a light-emitting device according to  claim 3 , wherein the stress is light. 
   
   
     10. An evaluation method of a light-emitting element material according to  claim 1 , wherein the light-emitting element material is evaluated by difference between the first absorption intensity and the second absorption intensity. 
   
   
     11. An evaluation method of a light-emitting element material according to  claim 2 , wherein the light-emitting element material is evaluated by difference between the first absorption intensity and the second absorption intensity. 
   
   
     12. A manufacturing method of a light-emitting device according to  claim 3 , wherein the light-emitting element material is evaluated by difference between the first absorption intensity and the second absorption intensity. 
   
   
     13. A manufacturing method of a light-emitting device according to  claim 3 , wherein the light-emitting device is incorporated into an electric appliance selected from the group consisting of a laptop personal computer, a portable phone, a television receiver, a car navigation system, a camera, and a lighting apparatus. 
   
   
     14. A manufacturing method of a light-emitting device according to  claim 3 , wherein the first electrode and the second electrode are formed by a material selected from the group consisting of indium tin oxide, indium tin oxide containing silicon oxide, indium oxide containing 2 to 20% of zinc oxide, gold, platinum, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, aluminum, an alloy of magnesium and silver, and an alloy of aluminum and lithium.